LONDON - Rafa Nadal and Maria Sharapova led a parade of former champions into the Wimbledon second round on Tuesday after Marion Bartoli briefly lit up Centre Court without swinging her racket. An order of play littered with big names began with a tearful Bartoli enjoying a standing ovation from a packed Centre Court as she returned to the scene of her triumph last year.Having retired a few weeks after her fairytale run at Wimbledon the Frenchwoman no longer has to contend with the stress and strain of the tour but for twice former champion Nadal and 2004 winner Sharapova, there is no respite. Just 16 days after claiming an unprecedented ninth French Open crown, Nadal was forced to fend off big-hitting Slovakian Martin Klizan in a ferocious Centre Court duel.Wary of his hopes withering early again after winning only one match in his previous two visits to the grasscourt citadel in south west London, Nadal initially looked in peril as he lost the first set before winning 4-6 6-3 6-3 6-3 to rack up his 700th main tour win. Russian fifth seed Sharapova, like Nadal, is also attempting to complete a daunting Roland Garros-Wimbledon double but unlike the Spaniard was able to conserve energy for the battles ahead with a 6-1 6-0 thrashing of British wildcard Samantha Murray.Seven-times champion Roger Federer, relegated to the Court One for the day, stole the show, however, with a dazzling 6-1 6-1 6-3 defeat of Italian journeyman Paolo Lorenzi. Lleyton Hewitt, the 2002 champion, led an impressive Australian charge when the 33-year-old warrior beat Poland's Michal Przysiezny in four sets to open his 61st grand slam tournament in typically pugnacious fashion.Serena Williams began her quest for a sixth women's singles title with a 6-1 6-2 victory over fellow American Anna Tatishvili on Centre Court after the All England Club gave the honour of opening play on what is known as Ladies Day to last year's runner-up Sabine Lisicki. In normal circumstances Bartoli would have played Centre Court's opening match - the honour traditionally bestowed on the defending women's champion on the first Tuesday of the slam. She still honoured her appointment, albeit clad in a summery cream outfit and platform shoes rather than tennis attire as she milked the applause before play began. Holding her hand was a young player from the tennis academy for disadvantaged children that was set up by British player Elena Baltacha, who recently succumbed to cancer. It was a typically classy piece of organisation by the All England Club and a moving moment for Bartoli."I'm sorry I got so emotional - I couldn't hold my tears being on the Centre Court and supporting #Rally4Bally at Wimbledon," Bartoli said on Twitter. As it turned out Lisicki performed the stand-in role beautifully, easing past Israel's Julia Glushko 6-2 6-1. For all the early theatre, it was Nadal who provided the day's real drama as he flirted with danger.Trailing by a set and staring at two breaks points on his serve early in the second it seemed the 28-year-old's recent grasscourt gremlins were returning. Defeat by dreadlocked German Dustin Brown in Halle this month had hardly fuelled Nadal's confidence but he reacted with typical ferocity to win. The world No.1, seeded two at Wimbledon, will now get the chance to gain revenge for his harrowing second round defeat by hard-hitting Czech Lukas Rosol two years ago."I am excited to be back here, to win a match at Wimbledon on Centre Court," the 2008 and 2010 champion told reporters. "When you go on court and you lost last year in the first round, the year before in the second round, I'm not going to lie it stays in your mind."Federer's staggering Wimbledon record was rudely interrupted in the second round by Sergiy Stakhovsky last year but the 32-year-old Swiss looked in the mood to mount a title challenge as he swept past Lorenzi for his 269th grand slam match victory. "I'm very happy getting through my first round. I thought I played very well," the 17-time grand slam champion said. "What you want to feel is inspired and motivated. I'm trying to win the tournament, that's what I'm here for."Fellow Swiss Stanislas Wawrinka can only marvel at Federer's feats at Wimbledon, but the fifth seed at least managed to avoid a sixth first-round exit on Tuesday, overpowering Portuguese claycourt specialist Joao Sousa 6-3 6-4 6-3. Twice former semi-finalist Jo-Wilfried Tsonga needed only four points to seal a first-round win over seasoned Austrian Juergen Melzer, the 14th seed winning 6-1 3-6 3-6 6-2 6-4 after rain stopped play on Monday with the Frenchman serving for the match.In the women's draw American Madison Keys, tipped as a dark horse for the title after winning in Eastbourne last week, cruised past Puerto Rico's Monica Puig, while 2012 runner-up Agnieszka Radwanska, the fourth seed, had little trouble against Romanian Andreea Mitu. Former world No.1 Caroline Wozniacki, seeded 16, beat Shahar Peer 6-3 6-0 but Jelena Jankovic became the highest women's seed, at number seven, to fall when she lost in straight sets to Estonian Kaia Kanepi.